Question

The radii of two cylinders are in the ratio 3 : 4 and their heights are in the ratio 8 : 5. The ratio of their volumes is equal to:
1. 7 : 10
2. 9 : 11
3. 9 : 10
4. 8 : 9

Answer 1

Correct Answer - Option 3 : 9 : 10

Given-   

Ratio of radii of two cylinders = 3 : 4

Ratio of height of two cylinders = 8 : 5

Formula Used-

Volume of cylinder = πr²h       [where r = radius of base and h = height] 

Calculation- 

Let the radii of two cylinders be 3x and 4x and their heights be 8y and 5y 

Volume of 1st cylinder : Volume of 2nd cylinder = π(3x)² × 8y : π(4x)² × 5y

⇒ 72xy : 80xy

⇒ 9 : 10 

The ratio of their volumes is equal to 9 : 10